题干

 下列四个实验方案设计不合理的是(  )

选项

实验目的

方案

A

鉴别硝酸钠溶液和硫酸钾溶液

取样,滴加Ba(NO32溶液,观察现象

B

除去粗盐中的难溶性杂质

将粗盐研碎、溶解、过滤、蒸发

C

除去CaO中的CaCO3

高温加热到固体质量不变

D

探究Mg、Ag、Cu金属的

活动性顺序

将两根光亮的镁条分别伸入

硫酸铜溶液和硝酸银溶液中

A:A

B:B

C:C

D:D

上一题 下一题 0.0难度 选择题 更新时间:2015-01-07 08:50:34

答案(点此获取答案解析)

D

同类题2

史实与推论:在人类历史上,社会进步往往与重大改革相伴而生,与科技创新息息相关。科学全面地解读史实或史料,可以得出正确的历史推论。请对下面的推论作出判断。

史实或史料

推论

判断

“商君教秦孝公以连什伍,设告坐之过,燔诗书而明法令” ----《韩非子·和氏》

商鞅变法这一措施体现了“以德治国”的理念。


他(达·芬奇)是画家、雕塑家、数学家,还是一名哲学家……(他)以新奇的目光重新审视一切的勇气和热情,才能使人类精神从经院的暗室,冲向色彩缤纷的新天地

----侯建新《社会转型时期的西欧与中国》

他“新奇的目光”中蕴含着的是人文主义的时代精神。


“在剑桥大学,牛顿是一个典型的工作狂。他几乎从来不参加娱乐活动,经常工作到凌晨两三点钟,有时干脆忘记了吃饭。”

----《大国崛起·英国》

牛顿废寝忘食地工作,取得的最主要成就是提出了相对论,为原子能的开发提供了理论依据。


……日本人把移植外来文化视为当然的事情,只要能够适应形势,任何需要的东西都可以从海外引进,既无顾虑也不以为耻。

----吴于廑、齐世荣《世界史·近代史编》

日本勇于吸收外来文化推动社会进步,对我国继续深化改革、扩大开放具有借鉴意义。


1921年俄共布“十大”后,受第一个在苏俄经营租让企业的美国人哈默劝说,大资本家亨利·福特到俄国开办企业。

哈默、福特之所以能在苏俄开设工厂,主要是因为苏俄实行了经济政策。


罗斯福称“产业复兴法”“是美国国会制定的最重要、最有深远意义的立法。”美国的工业产值1935年比1933年几乎翻了一番。

罗斯福新政创造了“国家干预经济”的模式,加强了政府对工业的计划指导,彻底避免了资本主义经济危机的发生。


同类题5

阅读下列短文,从每题所给的四个选项(A、B、C和D)中选出最佳选项。

A

    When I was a little kid, a father was like the light in the fridge. Every house had one, but no one really knew what either of them did when the door was shut.

    My dad left the house every morning and always seemed glad to see every one again at night. He opened the jar of pickles when no one else at home could. He was the only one in the house who wasn't afraid to go into the basement by himself. 

    Whenever it rained, he got into the car and brought it around to the door. When anyone was sick, he went out to get the prescription(处方) filled. He set mousetraps. He cut back the roses so the thorns(刺) wouldn't hurt you when you came to the front door. He oiled my roller skates, and they went faster. When I got my bike, he ran alongside me for at least a thousand miles until I got the hang of it. He signed all my report and cards. He took a lot of pictures, but was never in them. He tightened up Mother's sagging(松垂的) clothesline every week or so.

    I was afraid of everyone else's father, but not my own. 

    Whenever I played house(玩过家家), the mother doll had a lot to do. I never knew what to do with the daddy doll, so I had him say, “I'm going off to work now,” and threw him under the bed.

    When I was nine years old, my father didn't get up one morning and go to work, he went to the hospital and died the next day. 

    There were a lot of people in the house who brought all kinds of good food and cakes. We had never had so much company before.   

    He never did anything; I didn't know his leaving would hurt so much.